In this paper we discuss various aspects of systematic or conventional polysemy and their formal treatment within an implemented constraint based approach to linguistic representation. We distinguish between two classes of systematic polysemy: constructional polysemy, where a single sense assigned to a lexical entry is contextually specialised, and sense extension, which predictably relates two or more senses. Formally the rst case is treated as instantiation of an underspecied lexical entry and the second by use of lexical rules. The problems of distinguishing between these two classes are discussed in detail. We illustrate how lexical rules can be used both to relate fully conventionalised senses and also applied productively to recognise novel usages and how this process can be controlled to account for semi-productivity by utilising probabilities. 1 Introduction Discussion of polysemy has been central to much recent work on lexical semantics. Most of the arguments for (or again...

The LinGO (Linguistic Grammars Online) project's English Resource Grammar and the LKB grammar development environment are language resources which are freely available for download for any purpose, including commercial use (see http://lingo.stanford.edu). Executable programs and source code are both included. In this paper, we give an outline of the LinGO English grammar and LKB system, and discuss the ways in which they are currently being used. The grammar and processing system can be used independently or combined to give a central component which can be exploited in a variety of ways. Our intention in writing this paper is to encourage more people to use the technology, which supports collaborative development on many levels.

This thesis presents accounts of a range of linguistic phenomena in an extended categorial framework, and develops proposals for processing grammars set within this framework. Linguistic phenomena whose treatment we address include word order, grammatical relations and obliqueness, extraction and island constraints, and binding. The work is set within a flexible categorial framework which is a version of the Lambek calculus (Lambek, 1958) extended by the inclusion of additional type-forming operators whose logical behaviour allows for the characterization of some aspect of linguistic phenomena. We begin with the treatment of extraction phenomena and island constraints. An account is developed in which there are many interrelated notions of boundary, and where the sensitivity of any syntactic process to a particular class of boundaries can be addressed within the grammar. We next present a new categorial treatment of word order which factors apart the specification of the order of a h...

We define an order independent version of default unification on typed feature structures. The operation is

This thesis is an investigation of the representation of lexical semantic information from a computational linguistic perspective. An implemented representation language is described which is not specic to lexical semantics, but is based on the use of typed feature structures augmented with default operations. This language, which is formally specied, allows the lexical semantic representations to be tightly integrated with the syntactic component of the lexical sign, capturing generalisations by use of inheritance, while allowing for exceptions with the default mechanism. Default inheritance and default unication are discussed in detail. Grammar rules and lexical rules can be specied in the same formalism and thus the paradigmatic treatment of lexical semantics can be integrated with an account at the syntagmatic level. The use of the language is illustrated with some examples of the representation of verbs, the treatment of logical metonymy and of sense extension. This is followe...

Concrete inanimate animate liquid gas plant animal human solid moveable not-moveable Figure 2.4: LDOCE semantic space space by keeping to a simple hierarchy. However, it seems likely that a lot of specific predicates will not be adequately catered for. For example, given the 16 core categories depicted in figure 2.4 the direct object slot of sail would have to be accounted for by the movable class, when a more specific classification would be useful to distinguish, for example, cars, stones and ships. There are now WordNet versions for some European languages other than English (Vossen, 1999). For other languages, producing a new man-made hierarchy is not an easy alternative. The coverage needed for even a restricted domain requires considerable human effort. The noun hyponym hierarchy of WordNet is used as the representation medium for the preferences within this thesis. This makes our preferences prone to the human error inherent in the hierarchy and characteristic of any manmade resource. However, this is to some extent outweighed by the rigorous human effort that has gone into creating this useful taxonomy. WordNet has in excess of 60,000 classes in the hyponym hierarchy with over 88,000 word forms (version 1.5). Using current automatic classification methods for building a hierarchy of reasonable size would require considerable effort in post-editing to avoid incongruous classes and considerable processing time in the first place (Resnik, 1993a). The preferences we obtain are limited to the distinctions made within WordNet. Using corpus data does, to some extent, allow us to obtain preferences for the sublanguage of the corpus, since areas of WordNet that are not relevant to the domain have negligible frequency counts. 2.3 The WordNet Approaches There is a...

lexical rule example.

Abstract not found

The paper shows how the verbal lexicon can be formalised in a way that captures and exploits generalisations about the alternation behaviour of verb classes. An alternation is a pattern in which a number of words share the same relationship between a pair of senses. The alternations captured are ones where the different senses specify different relationships between syntactic complements and semantic arguments, as between bake in "John is baking the cake" and "The cake is baking". The formal language used is DATR. The lexical entries it builds are as specified in HPSG. The complex alternation behaviour shared between families of verbs is elegantly represented in a way that makes generalisations explicit, avoids redundancy, and offers practical benefits to computational lexicographers.

Introduction A major goal of a linguist writing hpsg theories is to express very general constraints to capture linguistic phenomena, leaving as much as possible underspecified. When such a hpsg theory is implemented faithfully, either processing is inefficient because only little information is available to guide the constraint resolution process, or the linguistic theory is annotated with information to guide processing. Usually such annotations are provided manually -- a very time consuming and error-prone process which can change the original linguistic theory. In this paper we show that it is possible to automatically make a theory more specific at those places where linguistically motivated underspecification would lead to inefficient processing. The authors are listed alphabetically. Authors' respective addresses: Seminar fur Sprachwissenschaft, Universitat Tubingen, Kl. Wilhelmstr. 113, D-72074 Tubingen, Germany; dm@sfs.nphil.un